While both require similar heat, it is not really recommended that you keep chicks and ducklings together because of a few reasons. First, ducklings need water to digest their food, and they are very messy with flinging the water around and trying to swim in the water dish. This would quickly make the bedding too wet for the chicks. Also, their food requirements are quite different. Not to mention that if you are feeding your chicks a medicated feed, it could prove fatal to the ducklings if they ate it. Also, I believe ducks grow much faster than chicks, and the size difference could cause an issue. Although, if you only have one brooder and want to rear both, it could be done by seperating the box with chicken wire or similar to keep chicks on one side and ducklings on another, and hang the lamp right over the middle so they all benefit. That way, they 'grow up' together and get used to each other, but are kept seperate for health and safety purposes. I'm sure someone here has raised both and will pop in with other sugestions.
